In general, normal cells control their division and growth precisely in the body. However, when cells lose their regulatory function or divide and grow uncontrollably, they are abnormally over-proliferated, thereby forming malignant tumors. Cancer cells may also spread to other sites in the body. That is, cancer cells growing in a primary cancer may invade neighboring tissues directly, or be metastasized to more distant parts of the body along with the blood vessel or lymphatic vessel. Since cancer cells can freely pass through both the lymphatic system and the venous system, they are broadly metastasized by their vascular spread. Blood-borne cancer cells pass through vascular endothelial cells by aggregation and invasion, thereby entering into the blood stream.
Meanwhile, 67 kDa laminin receptor (LR) is a non-integrin type receptor embedded in plasma membrane and associated with cancer invasion and metastasis (Nelson, J. et al. The 67 kDa laminin receptor: structure, function and role in disease. Biosci. Rep. 28, 33-48 (2008)). LR is often observed at high level in a various cancers (Nelson, J. et al. The 67 kDa laminin receptor: structure, function and role in disease. Biosci. Rep. 28, 33-48 (2008); Menard, S., Castronovo, V., Tagliabue, E. & Sobel, M. E. New insights into the metastasis-associated 67 kD laminin receptor. J. Cell. Biochem. 67, 155-165 (1997)). It has been reported that the laminin signals mediated by LR induce cancer progress and metastasis, through various signaling pathways associated with a G protein, FAK, MAPK, a phosphatase, a phospholipase D, etc (Cancer Letter, 2005).
Recently, it was found that Lysyl-tRNA-synthetases (KRS), one of the aminoacyl-tRNA synthetases (ARSs), bind to laminin receptor (LR) so as to stabilize the laminin receptor (LR). That is, it was reported that KRS facilitates cell migration and cancer metastasis by stabilizing the laminin receptor (LR) and that KRS over-expression leads to increase in metastasis (WO 2011/056021). And also, it was reported that inhibition of the binding between KRS and the LR protein degrades the LR protein, thereby inhibiting cell migration and leading to the inhibition of cancer metastasis in animal models (Nature Chemical Biology, 2014, 10: 29-34).
Therefore, it is expected that a material inhibiting or blocking the interaction between KRS and LR can inhibit or block cancer metastasis, thereby usefully applying to prevention and treatment of cancer.